Are Arkansas' Natural Gas Injection Wells Causing Earthquakes?

Hundreds of small and medium-scale earthquakes have been rattling the area around Guy, Ark., and residents say wastewater injection wells being drilled in their area are to blame.

"It gives new meaning to the term 'rock your world,'" said resident Johnny Passmore. "There is no foundation. You are just shaking and you can't go anywhere because it's shaking."

In February, shocks from a 4.7-magnitude earthquake near the town were felt as far away as Memphis, Tenn., the biggest quake in the region in 35 years.

These earthquakes are the newest development in the raging national argument over the safety of drilling for natural gas.

Josh Fox, the director of the Oscar-nominated documentary, "Gasland," questioned the industry's claims of natural gas as a clean energy source. His film is critical of a drilling method called hydraulic fracturing, otherwise known as "fracking," where fluid is injected into rock, breaking it to release natural gas.

In 2008, Fox said he was offered $100,000 to lease his 19 acres in Pennsylvania for natural gas drilling. He then launched a road trip across 24 states to investigate the environmental impact natural gas drilling was having on local communities.

Many of the families featured in the film told Fox they had developed health problems after leasing their land for hydraulic drilling. "Nightline" asked him to come with them to Arkansas to talk with people about their experiences with the earthquakes.

"People are your first level of scientific data," Fox told "Nightline." "You have to trust what the people are saying on the ground as your first level in any investigation."

Energy Companies Respond to Earthquakes

Just days after the 4.7-magnitude quake in February, state regulators pressured energy companies into voluntarily shutting down two injection wells closest to the fault line. Chesapeake Energy, now owned by BHP Billiton, owned one of the wells at the time.

"We do not agree with the conclusions," said Chesapeake Energy spokesman Danny Games in a recent television interview. "We believe there is a lot of natural seismicity in this area and there's a lot more sub-surface data, and science and facts that need to be brought to bear."

A public hearing is scheduled Tuesday for both sides to present their data and decide whether or not the injection wells should be re-opened. There is a moratorium on building any new injection wells until this summer.

"We have to side with that public safety concern and address that in a way that maybe science does not totally support," said Larry Bengal, director of the Arkansas Oil and Gas Commission.

In the hills of the Arkansas River Valley, the treasured serenity has been shattered.

Resident Dirk DeTurck said the shaking began late last summer.

"The ground just rolls," he said. "It just rolls. And it's like a loud thunderclap and the house shakes at the exact same time ... a lot of sheet rock cracking."

Since the two injection wells were shut down in March, the earthquakes have not completed stopped in Arkansas. But Scott Ausbrooks, a geologist with the Arkansas Geological Survey and a lead detective on the case, said they have tapered off dramatically.

"It's too much of a coincidence," DeTurck said.

Earthquake 'Felt Like You Were on a Roller Coaster'

Another resident, Susan Frey, described what it was like to be inside her home during one of the quakes.

"You felt like you were on a roller coaster or going down a hill or sitting on a rowboat in the middle of the ocean with somebody rocking the boat," she said.

Frey said the earthquakes became so frequent that she installed a plumb line to keep track of the ground's movements. She then recorded and posted the results on YouTube.

Ausbrooks said the area around Guy has had more than 1,100 earthquakes since September 2010. He said that the earthquakes are rattling the Arkansas countryside in part of what's known as the Fayetteville shale.

Since 2005, more than 3,000 gas wells have been drilled in this area, according to the Arkansas Oil and Gas Commission. While these wells provide thousands of jobs and billions of dollars in revenue to a destitute part of the country, Fox said they also produce tons of contaminated water -- an issue he widely addressed in "Gasland."

While in Arkansas, Fox said he will investigate a theory that the tremors can be traced to how wastewater from the thousands of "fracking" wells is handled.

Cracking the Cause of the Arkansas Quakes

Injection wells have pumped millions of gallons of wastewater -- the equivalent of a 30-acre lake -- deep into the ground, but gas companies insist no scientific evidence links the injection wells to earthquakes and that some quakes were recorded in the region before the wells were drilled.

Ausbrooks placed seismometers in parks and private backyards to get real-time data, and discovered the quakes are taking place along a new fault line that measured seven and a half miles long.

"If that was to rupture at all one time," he said, "then you could generate, theoretically, up to a magnitude 5.7 to 6.0 [earthquake]. ... It potentially could be a very dangerous earthquake, given the population area right here."